Gold and silver jewellery dating from 2,500BC has been discovered in a storeroom at the British Museum among relics first excavated in the 1920s.

Gold and silver jewellery dating from 2,500BC has been discovered in a storeroom at the British Museum among relics first excavated in the 1920s.

The adornments were part of the elaborate head-dresses worn by female attendants who had been buried alive in a royal tomb at the ancient Sumerian city of Ur in what is now southern Iraq.

Some of the material excavated from the site more than 70 years ago had been hurriedly preserved in blocks of paraffin wax before being shipped back to London.

When the museum's scientists X-rayed two blocks of wax labelled "crushed skulls", they found two bejewelled head-dresses worn by female courtiers who had been buried with their king more than 4,000 years ago.

The head-dresses consist of wreaths of gold leaves held together with strings of lapis-lazuli beads probably worn low over the forehead. Ribbons of gold and silver had been festooned over the wearer's hair, which was probably embellished with large wigs held by ornate hair combs decorated with rosettes.

Each comb consisted of a flattened metal pin split into three prongs and finished with inlaid flowers whose petals were a mixture of lapis, shell, gold leaf and pink limestone.

X-rays showed lengths of twisted wires ran between each flower-head. These probably held the florets securely in place within a mass of braided hair, according to Janet Ambers, the radiographer who carried out the study. "Alternatively, the chain was part of the decoration. It could have moved and thus caught the light as the wearer walked," said Ms Ambers.

The discovery has shed light on the death rites of the Mesopotamians. Little is known about their funerary arrangements, despite the discovery in the 1920s and 1930s of 16 royal tombs and 1,800 graves by the British archaeologist Sir Leonard Woolley.

Ur was inhabited from about 5,900BC until about 400BC when it was finally abandoned after the river Euphrates changed its course, turning fertile land into desert.

The burial site was called the great death pit because it contained the largest number of skeletons - 68 women guarded by six men armed with knives and axes - around a central burial chamber that had long been destroyed, probably by tomb robbers.

All the women were heavily adorned with gold, silver, lapis lazuli and cornelian jewellery and their skeletons were arranged in rows running north-west to south-east.

Archaeologists believe they probably died by poisoning. Small jars next to some of the bodies suggest that the attendants drank a sedative drug such as an opiate rather than an extreme toxin such as hemlock or cyanide which would have caused writhing and contortions.

Because many of the objects at the site are so fragile, Woolley would have lifted blocks of material from the ground and poured melted candles or plaster of Paris over them before shipping them back to Britain.

The most prevalent theory on the identity of the skeletons and the circumstances of their deaths is that they were members of the royal household who willingly accompanied their master to the afterlife. Other suggestions depict them as part of a suicide cult connected to the worship of the god Inanna or slaves dressed up to represent royal courtiers who preferred to live on.

Whoever they were, their last walk to the tomb must have been an impressive affair, said Alexandra Irving, a curator of Mesopotamian art at the British Museum. "With these pieces catching the light and making slight sounds as the wearer moved, the final journey of the attendants to their resting place must have been an awesome sight."